Optimal Selection of Conductors for Distribution Feeders

Abstract: Solution methodology of unit commitment using geneticalgorithms (Gas) is presented. Problem formulation of the unit commit-ment takes into consideration the minimum up and down time con-straints, start-up cost, and spinning reserve, which is defined asminimization of the total objective function while satisfying the associ-ated constraints. Problem-specific operators are proposed for the satis-faction of time-dependent constraints. Problem formulation,representation, and the simulation results for a 10-generator-schedul-ing problem are presented.

Keywords: Optimization, genetic algorithms, unit commitment,economic dispatch.

Preprint Order Number: PE-006PRS (10-2001)Discussion Deadline: March 2002

Application of ATM-Based Network for anIntegrated Distribution SCADA-GIS System

Huang, S.J.; Lin, C.C.

Author Affiliation: National Cheng Kung University, TaiwanAbstract: In this paper, an asynchronous transfer mode

(ATM)-based network is applied as the communication backbone be-tween a geographical information system (GIS) and supervisory controland data acquisition (SCADA). Because the ATM network is a truemultiservice network that provides broadband services and meets thedifferent quality of service requirements, this technique is increasinglyimportant in a modem communication system. The paper begins with theevent generator that brings different messages to the ATM network fromvarious local area networks. A statistical evaluation is then employed toexamine the amount of message flow and the quality of service, wherethe outcome is assessed based on traffic, capacity, and performance ofthe proposed method. Test results help solidify the effectiveness of theapproach for power system communication applications.

Keywords: ATM, GIS, SCADAPreprint Order Number: PE-047PRS (10-2001)Discussion Deadline: March 2002

Power System Planning and Implementation

Distributed Utility Planning UsingProbabilistic Production Costingand Generalized Benders DecompositionMccusker, Susan; Hobbs, B.; Ji, Y.

Author Affiliation: Energy Resources Intemational; The JohnsHopkins University, Baltimore, MD: Boca Photonics, Boca Raton, FL

Abstract: Regulatory changes and advances in distributed re-sources (DR) technology have lead utilities to consider DRs as altema-tives to central station generation and T&D investments. This paperpresents a comprehensive planning and production simulation modelthat simultaneously evaluates central and local investments to deter-mine the optimal mix for long-term expansion. The model can also beviewed as optimizing DRs while simulating a perfectly competitivewholesale power market. The model is a mixed integer linear stochasticprogram that enforces Kirchhoff's current and voltage laws, and issolved using generalized Benders decomposition (GBD). The formula-tion includes multiarea probabilistic production costing as asubproblem. DRs and local distribution reinforcements are modeled asinteger variables, while transmission and central generation options arerepresented as continuous variables. The model is applied to a ten-yearmulti-area example that suggests that DRs are able to modify capacityadditions and production costs by changing demand and power flows.

Keywords: Power generation planning, distributed resources, eco-nomics, market model, demand-side management.

Preprint Order Number: PE-358PRS (10-2001)Discussion Deadline: March 2002

Optimal Selection of Conductorsfor Distribution Feeders

Mandal, S.; Pahwa, A.

Author Affiliation: Kansas State University, Manhattan, KSAbstract: Designing a distribution system requires many stages of

planning and rigorous calculations. Selection of conductors for designand upgrade of distribution systems is an important part of the planningprocess. An ideal conductor set should have the most economic costcharacteristics and sufficient thermal capacity in the largest conductorto take care of situations with very high load, and it should provideproper voltage at the farthest end under peak load conditions. In this pa-per, a method for selection of an optimal set of conductors is presented.Several financial and engineering factors are considered in the solution.The intent is to arrive at a solution that will be the most economicalwhen both capital and operating costs are considered. Simulations havebeen performed to obtain results based on different criteria and the re-sults are compared.

Keywords: Costs, economics, planning, power distribution, powerdistribution lines, power system planning.

Preprint Order Number: PE-1O5PRS (10-2001)Discussion Deadline: March 2002

Probalistic Assessment of PhotovoltaicGeneration Systems

Maghraby, H.A.M.; Shwehdi, M.H.; Al-Bassam, G.K.

Author Affiliation: King Fahd University of Petroleum & Min-erals, Dhahran, Saudi Arabia; Saudi Aramco Oil Co., Dhahran, SaudiArabia

Abstract: The sizing of photovoltaic (PV) power systems for re-mote offshore loads has been the concem of end users. This is becauseof the space constraints associated with the application and the expen-sive cost of panels and batteries. This paper evaluates the design of thePV system using three probabilistic methods. One is considering fixeddays of battery back up and recharge and the other is based on loss ofload probability (LOLP). The third is based on Markov chainmodeling. LOLP distinctly shows reduction in the number of panelsand size of batteries while providing a detailed view of the system per-formance.

Keywords: Reliability, photovoltaic, Markov chain, LOLP, proba-bilistic analysis, optimization of PV systems.

Preprint Order Number: PE-670PRS (10-2001)Discussion Deadline: March 2002

Power System Relaying

Application of a Wide Area Backup ProtectionExpert System to Prevent Cascading Outages

Tan, J.C.; Crossley, P.A.; Laren, P.G.M.; Gale, P.F.; Hall, I.;Farrell, J.

Author Affiliation: University of Manitoba, Winnipeg, MB, Can-ada; UMIST, Manchester, U.K.; Hataway; NGC; Scottish Power

Abstract: A strategy to prevent cascading outages in power sys-tems is proposed in this paper. The strategy employs wide-area back-upprotection and artificial intelligence techniques to minimize the impactof a fault on a network. There are two ways in which wide-area backupprotection can prevent cascading trips leading to a wide spread black-out: 1) Precise location of a fault so that only the circuit breakers neces-sary to isolate the fault are tripped; and 2) Avoidance of unnecessarytrips, due to hidden failure or overloading, by blocking the trip signalsof conventional back-up protection relays. The limitations of conven-tional back-up protection are examined and methods of improvementare presented.

IEEE Power Engineering Review, January 2002 71